Re: (ET) Update my my old "cooked" Trojan batteries

["David Roden" <etpost drmm net>]

On 26 Aug 2009 at 18:17, David Barden wrote:

> other than having to add water a little more frequently, what's the harm 
> of
> "overcharging" anFLA battery?

I'm puzzled as to why you put overcharging in quotation marks.  It's not a 
theoretical or imaginary matter; overcharging accelerates depreciation of 
a 
battery, period.  In any battery, overcharging causes more rapid corrosion 
of the positive grids, shortening the battery's life.  

In valve regulated (closed AGM or gel) if the overcharging causes gassing 
beyond what the recombinant reaction can handle, it also contributes to 
loss 
of water, which can't be replaced (at least not without voiding the 
warranty).

This is the reason that UPS batteries have to be replaced every few years 
whether the computer (or whatever) uses the UPS or not.

On the other hand, chronic undercharging can cause hard crystalline 
sulfation. Shed sulfate crystals are gone forever.  This kind of sulfation 
is irreversible, no matter what the blinky gadget and snake oil 
manufacturers claim.

Now, the question is, which does more harm, overcharing or undercharging?  
That's not easy to answer.  But it appears to me (from very unscientifc 
observations) that overcharging is probably more common than 
undercharging. 
It's also my opinion that in cyclic use, where the battery is cycled 
regularly, slight undercharging is preferable to overcharging.  But you 
can 
easily find some very knowledgable folks who will say the opposite, so 
take 
your pick. ;-)


David Roden - Akron, Ohio, USA

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 
Note: mail sent to the "etpost" address will not reach me.  To send 
me a private message, please use the address shown at the bottom
of this page : http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =